/*
   Demo Name:  Lines
      Author:  Allen Sherrod
     Chapter:  Ch 1
*/


#include<d3d9.h>

#pragma comment(lib, "d3d9.lib")
#pragma comment(lib, "d3dx9.lib")

#define WINDOW_CLASS L"UGPDX"
#define WINDOW_NAME  L"Drawing Lines"

// Function Prototypes...
bool InitializeD3D(HWND hWnd, bool fullscreen);
bool InitializeObjects();
void RenderScene();
void Shutdown();


// Direct3D object and device.
LPDIRECT3D9 g_D3D = NULL;
LPDIRECT3DDEVICE9 g_D3DDevice = NULL;

// Vertex buffer to hold the geometry.
LPDIRECT3DVERTEXBUFFER9 g_VertexBuffer = NULL;


// A structure for our custom vertex type
struct stD3DVertex
{
    float x, y, z, rhw;
    unsigned long color;
};

// Our custom FVF, which describes our custom vertex structure.
#define D3DFVF_VERTEX (D3DFVF_XYZRHW | D3DFVF_DIFFUSE)


LRESULT WINAPI MsgProc(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp)
{
   switch(msg)
      {
         case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
            break;

         case WM_KEYUP:
            if(wp == VK_ESCAPE) PostQuitMessage(0);
            break;
      }

   return DefWindowProc(hWnd, msg, wp, lp);
}


int WINAPI WinMain(HINSTANCE hInst, HINSTANCE prevhInst,
                   LPSTR cmdLine, int show)
{
   // Register the window class
   WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, MsgProc,
                     0, 0, GetModuleHandle(NULL), NULL, NULL,
                     NULL, NULL, WINDOW_CLASS, NULL };
   RegisterClassEx(&wc);

   // Create the application's window
   HWND hWnd = CreateWindow(WINDOW_CLASS, WINDOW_NAME,
                            WS_OVERLAPPEDWINDOW, 100, 100,
                            640, 480, GetDesktopWindow(), NULL,
                            wc.hInstance, NULL);

   // Initialize Direct3D
   if(InitializeD3D(hWnd, false))
      {
         // Show the window
         ShowWindow(hWnd, SW_SHOWDEFAULT);
         UpdateWindow(hWnd);

         // Enter the message loop
         MSG msg;
         ZeroMemory(&msg, sizeof(msg));

         while(msg.message != WM_QUIT)
            {
               if(PeekMessage(&msg, NULL, 0U, 0U, PM_REMOVE))
                  {
                     TranslateMessage(&msg);
                     DispatchMessage(&msg);
                  }
               else
                  RenderScene();
            }
      }

   // Release any and all resources.
   Shutdown();

   // Unregister our window.
   UnregisterClass(WINDOW_CLASS, wc.hInstance);
   return 0;
}


bool InitializeD3D(HWND hWnd, bool fullscreen)
{
   D3DDISPLAYMODE displayMode;

   // Create the D3D object.
   g_D3D = Direct3DCreate9(D3D_SDK_VERSION);
   if(g_D3D == NULL) return false;


   // Get the desktop display mode.
   if(FAILED(g_D3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT,
      &displayMode))) return false;


   // Set up the structure used to create the D3DDevice
   D3DPRESENT_PARAMETERS d3dpp;
   ZeroMemory(&d3dpp, sizeof(d3dpp));


   if(fullscreen)
      {
         d3dpp.Windowed = FALSE;
         d3dpp.BackBufferWidth = 640;
         d3dpp.BackBufferHeight = 480;
      }
   else
      d3dpp.Windowed = TRUE;
   d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
   d3dpp.BackBufferFormat = displayMode.Format;


   // Create the D3DDevice
   if(FAILED(g_D3D->CreateDevice(D3DADAPTER_DEFAULT,
      D3DDEVTYPE_HAL, hWnd, D3DCREATE_HARDWARE_VERTEXPROCESSING,
      &d3dpp, &g_D3DDevice))) return false;


   // Initialize any objects we will be displaying.
   if(!InitializeObjects()) return false;

   return true;
}


bool InitializeObjects()
{
   unsigned long col = D3DCOLOR_XRGB(255, 255, 255);

   // Fill in our structure to draw an object.
   // x, y, z, rhw, color.
   stD3DVertex objData[] =
      {
         { 420.0f, 150.0f, 0.5f, 1.0f, col, },
         { 420.0f, 350.0f, 0.5f, 1.0f, col, },
         { 220.0f, 150.0f, 0.5f, 1.0f, col, },
         { 220.0f, 350.0f, 0.5f, 1.0f, col, },
      };

   // Create the vertex buffer.
   if(FAILED(g_D3DDevice->CreateVertexBuffer(sizeof(objData), 0,
             D3DFVF_VERTEX, D3DPOOL_DEFAULT, &g_VertexBuffer,
             NULL))) return false;

   // Fill the vertex buffer.
   void *ptr;

   if(FAILED(g_VertexBuffer->Lock(0, sizeof(objData),
      (void**)&ptr, 0))) return false;

   memcpy(ptr, objData, sizeof(objData));

   g_VertexBuffer->Unlock();

   return true;
}


void RenderScene()
{
   // Clear the backbuffer.
   g_D3DDevice->Clear(0, NULL, D3DCLEAR_TARGET,
                      D3DCOLOR_XRGB(0,0,0), 1.0f, 0);

   // Begin the scene.  Start rendering.
   g_D3DDevice->BeginScene();

      // Render object.
      g_D3DDevice->SetStreamSource(0, g_VertexBuffer, 0,
                                   sizeof(stD3DVertex));
      g_D3DDevice->SetFVF(D3DFVF_VERTEX);
      g_D3DDevice->DrawPrimitive(D3DPT_LINELIST, 0, 2);

   // End the scene.  Stop rendering.
   g_D3DDevice->EndScene();

   // Display the scene.
   g_D3DDevice->Present(NULL, NULL, NULL, NULL);
}


void Shutdown()
{
   if(g_D3DDevice != NULL) g_D3DDevice->Release();
   if(g_D3D != NULL) g_D3D->Release();
   if(g_VertexBuffer != NULL) g_VertexBuffer->Release();

   g_D3DDevice = NULL;
   g_D3D = NULL;
   g_VertexBuffer = NULL;
}